考虑渠内水影响的冬季输水渠道冻胀的数值模拟

Numerical simulation of influence of internal water on the frost heave of canal delivering water in winter

针对季冻区冬季输水混凝土梯形衬砌渠道在运行中的冻胀问题,本文进行水热力耦合模型数值模拟,分析渠道供水期渠内水对渠道冻胀量的影响。在利用水热力耦合模型,同时结合水热力相互作用方程和有限元分析方法对供水期的梯形混凝土衬砌渠道的3个基本物理场实施计算,并与停水期混凝土梯形衬砌渠道的三场实施对比,最后结合实测数据进行误差解析。结果表明:冬季输水混凝土梯形衬砌渠道的3个基本物理场与停水期明显不同,但根据模拟所得数据可建立冬季输水混凝土梯形衬砌渠道冻胀预测曲线,并经分析比对后发现预测构造曲线与原型观测曲线基本重合;季冻区冬季输水混凝土梯形衬砌渠道供水期与停水期的渠道最大冻胀量相差约65 mm,表现出显著差异。上述结果表明,渠内水是渠道冻融循环中热源补给的重要来源之一,是冻胀量产生差异的重要原因,因此在渠道冻胀研究中极有必要考虑渠内水的影响。

According to the frost heave problem of trapezoidal concrete lining canal with water during winter in seasonally frozen ground region, the numerical simulation of coupled heat-moisture-deformation model was carried out. The influence of internal water on the frost heave of canal was analyzed. Based on the combination of water heat coupling model of water thermal interaction equation and finite element analysis of three basic physical field on the trapezoidal concrete lining canal delivering water was calculated, and then compared the calculation results of canal delivering water and concrete lined trapezoidal canal with the measured data for error analysis. The results showed that trapezoidal concrete lining canal water supply period of the temperature field, stress field and deformation field is different from water cut period of trapezoidal concrete lining canal. In addition, the frost heave prediction curve was established by combining the observed values of freezing water movement, ground temperature and freezing depth. The predicted curve is basically consistent with the prototype observation curve. The maximum frost heave difference between canal water supply period and water cut period of trapezoidal concrete lining canal is about 65 mm in seasonally frozen ground region, which shows significant difference. The internal water is one of the important sources of heat in canal freezing and thawing cycles, which is the main reason for the difference of distribution of frost heaving, therefore in the study of frost heaving damage must be taken into consideration in canal water.